When I was a kid (1998-ish), I remember when this was mysteriously enabled. Because this feature didn't put viagra ads or porn on the internet, no one used it. Suddenly IE was completely unusable. It was like this for about 2 days until dad wanted to visit this new website he heard of, but couldn't. Because I warned him that he wouldn't be able to, he hounded me for the password. Turns out that the neighbor mentioned this feature to mom, and the neighbor turned it on. He said that his locksmith website had these ratings, so he pulled it up, only to be prompted with the 'this site is unrated' password dialog. Defeated, he turned it off.

In the meantime, the exchange student we were hosting was able to get a link to download Opera from one of the IRC chatrooms he always hung out in.